Manufacture of metallic receptacles



July 2, 1940. H. w. CLARK 2,205,733

MANUFACTURE OF METALLIC RECEPTACLES Original Filed Nov. 7, 1935 5 Sheets-Sheet 1 Fig.1.

l/ ww 2 18 -J J6 J8 19 m i j 1 I H Ha r'old wj 'lark MZM July 2, 1940. H. w. CLARK 2,206,763

MANUFACTURE OF METALLIC RECEPTACLES Original ir'iled Nov. '7, 1935 5 Sheets-Sheet 2 J? 5 5 INVENTOR Ha r'o/d- W. Clark July 2, 1940. H. w. CLARK 2,206,763

MANUFACTURE OF METALLIC RECEPTACLES Original Filed Nov. 7, 1935 3 Sheets-Sheet 5 LwJ INVENTOR Patented July 2, 1940 MANUFACTURE OF METALLIC BE CEPTACLES Harold W. Clark, Alliance, Ohio, assignor to The Steel Sanitary Company, Alliance, Ohio, a corporation of Ohio Original application November '7, 1935, Serial No. 48,664, now Patent No. 2,176,738, dated October 17, 1939. Divided and this application March 8,1939, Serial N0. 260,576

2 Claims. (Cl. 113-120) This invention relates to the manufacture of metal receptacles and, in particular, to receptacles made by the deep drawing of sheet steel. The invention will be disclosed as applied to the manufacture of bath tubs from sheet steel, but

it will be apparent that other articles of like nature may be produced by the same method and apparatus, or with only slight modifications Figure 2 is a transverse sectional View thereof;

Figure 3 is a plan view of the draw ring; Figure 4 is a longitudinal section through the tub section. produced by the apparatus of Figures 1 through'3; I

Figure 5 is a view similar to Figure 1 showing the apparatus for forming the other tub section; and t Figure 6 is a side elevation of the two sections thereof. This application is a division of my co- D I pending application, Serial No. 48,664, filed Noready o be Joined to ether by we dma vember '7, 1935,1'1ow Patent No. 2,176,738 October I l f to p y a so-called :toggle press 17, 1939. Certain other subject matter disclosed f r o mns the tu secti ns- As w ll known, in my said application Serial No. 48,664 and in h a m f m ha a p ss havin two this application but not claimed in either thereof ti r r y movable e r p ed is disclosed and claimed in my copending appli- QlJeFfiI-e a predetermined successmn. Since cations Serial Nos. 260,575 and260,577, riled of t nstruction of pres s 0i thls character is even date herewith, which are also divisions of 3 h t 15 not herein illustrated nor d my said copendmg n ti Seria1N0 43 4 scribed. It is sufiic ent to state that the press While it has been proposed heretofore to make l l p s table in the form of a q bath tube by deep drawing a single steel sheet, l er dap t upp h i s hr h J) so far as I am aware, this result has never been (h-F the sheet drawn, nd at least two Ver- Dbtained commercially, at least on a practical tifia ly movable slides adapted to operate in suc.

basis. While it is probably possible to draw a ga -fit p m our tub of conventional design from a smgle steel Ca -H 15 0 2 11 ga t g t hc a box-shaped w sheet. the amount of waste involved by the exi 1 an o om, is adapt d W cessive scrap produced is so great as to rule out @1511 f'I Ci g g 0f the pp l commerciau It has also been sur'ace iiereo is in ma ed y the line H. A ggilg gj fig to proyduce z tubs by draw ring 62 is secured to the bottom spacer it.

'20 forming a pluralityof tub sectlons and weld ng 111 ilgule o, the draw 1mg 1s subthem together. ThlS method has not met w1th w? angu @1111 Outlme and has an p 39 wide success because of the cost of welding the b 9 at f 1511? d of several joints and the problems introduced by th 32 5f g s g lfgvn gt Else sligzsupancll i n. e; c l e t1I; bath tubs w 0f the draw s I2 is provided with r505,

35 by joining only two sections by a circumferential gi f g SD fi f along the sides 5 seam or joint. This reduces the amount of weld- 101m e d of the op The purpose ing necessary to a minimum. The invention s giiil gf fc gi ai -231 5 521223651113 as the dei gjfi 5 5 1 iiiz g gigg gg ggg 23 pressure pad i6 is reciprocablewithin the 0 m u D 1 bottom snacer Hi by means of pneumatic cyl n- 40 cessive amount of scrap. In. accordance with my r v i i 1 CICPS 5? having pistons it siidable therei on invention. I draw a steel sheet througi a sui which the p rests The Supply of air bathe ably shaped die ring by means of a punch press ders H, is Controlled by any suitabl form of and restrain the flow of the metaladJacent the Waive indicated diagrammatically at m The edge of the Sheet Over the dJraW m insure upper surface of the Hi is concave as shown 5 pro-par Shaping of the resumng seamen Wlthout at fiil to assist in shaping metal sheet being the formation of wrinkles. folds or scratches. A drawn to the al combur desired hi the, finished present preferred embodiment of the invention product The pad 56, adjacent the flghtimand a preferred pract ce thereof are illustrated end as Shown in Figures 1 and is provided with 1n the accompanying draw ngs although it is to a transverse r ove 2!, the purpose of which will be understood that the inventlon may be otherbe gxplained Shortly wise embodied and practiced within the scope of A blank holder ring 22 is mou t d on one f h oc In thedrawmssr the slides of the press, specifically that whi f gure 1 .is l a longitudinal sectional view descends first. The slide on which the blank through the punch and die of my invention; holder ring is supported is indicated diagra 55 ing ribs or splines and grooves will serve to grip the edge of the plate, as indicated in Figures 1 and 2 and retard flow of the metal sheet therebetween as the central portion thereof is pressed inwardly and downwardly.

A punch 25 is mounted on an extension 26 secured to the other slide of the press, viz., that which descends last. The punch 25 is shaped to produce the desired contour of the finished tub section. A removable plate or shoe 2'! is secured to the lower face of the punch to permit the latter to be employed for making tub sections of different lengths. The plate 21 has a rib or spline 28 adapted to cooperate with the groove 2| in the pad It for the same purpose as the ribs and grooves in the draw ring and blank holder.

It will be observed that the sides of the punch are convex outwardly, as shown at 29. The re sulting tub section has a similar contour which is desirable in that it prevents reverse buckling such as is experienced due to expansion and contraction when enameling a tub having a flat or plane side wall. By curving the side wall of the tub, any buckling that may occur takes place in one direction only and is not reversible, with the result that the enamel coating is not fractured.

The operation of the apparatus already described will probably be apparent but will nevertheless be reviewed briefly. The toggle press is first operated so as to withdraw the punch 25 and the blank holder ring 22. A steel sheet, such as that shown at 30, is laid across the draw ring 12. The press is then operated so as to cause the blankholder ring 22 to descend and grip the sheet 30 adjacent its edges. The pad I6 is then raised to the position shown in chain lines, by manipulation of the valve Ill. The press is then operated so as to cause the punch 25 to descend and progressively shape the sheet from the fiat condition, through the intermediate stage shown in dotted lines in Figure 1, to the final form shown in solid lines in Figure 1. As the punch descends and deforms the sheet, the edges and central portion thereof are stretched and deformed and there is actually some fiow of the edges of the sheet between the draw ring and the blank holder ring. The cooperating splines and grooves on these parts, however, limit the inward flow of the sheet edges so that the deformation caused by the parts is largely taken up by the elongation of the central portion of the sheet. This makes it possible to employ as drawing stock a flat sheet having the minimum dimensions sufficient to form a tub so that the waste due to scrap is correspondingly reduced. At the same time the center portion of the blank is smoothly shapedto the desired contour. The pad 56 assists in giving the proper form to the finished tub section, being depressed against the air pressure in the cylinders H by the punch 25 as the latter descends. The spline 28 and the groove 2| act in the same man ner as the splines and grooves on the draw ring and blank holder ring, to limit fiow of the: sheet longitudinally of the punch and pad. While some flow occurs, the deformation is permittedlargely by the stretching of the center part of the sheet.

The finished tub section on removal from the draw ring has the appearance shown in Figure 4. The end of the section is then trimmed off along the chain line 3! and the edges'of the section sheared and flanged upwardly as shown at 32.

The method and apparatus above described, with some slight modification, may also be employed to form the drain end of a tub such as indicated at 33 in Figure 6, the finished bell end-being shown at 34 in the same figure. Figure 5 illustrates the apparatus which I prefer to employ for forming drain ends for tubs. This apparatus corresponds generally to that of Figures 1 through 3, including a bottom spacer 35, a draw ring 36 secured thereto, a pad 31 reciprocable within the spacer 35 on pneumatic cushions, a blank holder ring 38, a punch 39, and a punch extension 40. The draw ring 36 is similar to that shown at 12 but is of substantially U-shape in plan, being open atone end. The blank holder ring is closed and the punch extension 4!] is recessed at 4| to receive the inner cross member thereof. The draw ring and blank holder ring are provided with splines and grooves 42 and 43, as already described. The punch 39 differs from the punch 25 so as to give the finished drain end of the tub the proper shape. The pad 3'! is provided with a filler M. The inner end of the punch, furthermore, is inclined as at 45. As a result, the inner end of the blank or flat sheet is bent upwardly around the inclined end of the punch. This construction of the pad filler and punch serves the same purpose as the rib 28 and groove 2| of the punch and pad of Figure 1 except that the construction of Figure 5 exerts a greater force restraining fiow of the metal stock around the punch.

The operation of the modified form of apparatus shown in Figure 5 is similar to that already described, the only difierence being that the center portion of the inner end ofthe sheet of the metal adjacent the hole out of the general plane of the bottom of the drain end, as shown at 46. I find that this method prevents fracture of the metal which occurred when it was attempted to deform the material surrounding the hole before punching the hole itself.

While it is quite possible to form tub sections in a single pressing operation as described above, I have found that the operation can be somewhat facilitated by making it in two stages and annealing the partly formed sections after the first operation at a temperature of between 1300 and 1400 F.

After the tub sections shown in Figure 6 have been produced, they are ready for joining, for example. by electric welding and, after the welded joint has been ground down, the finished tub can be annealed in the usual manner.

It will be apparent from the foregoing description that the invention provides a simple and highly practical method-of making tubs or other similar receptacles from flat sheet metal by forming two sections each'in a single operation if desired, and joining them together. stated, the method and apparatus disclosed make possible the accomplishment of this result with a minimum of scrap material and dies, thus reducing the cost of the finished product.

Although I have illustrated and described but one preferred embodiment of the apparatus and ling of said sides during firing, welding to said blank a blank adapted to form the other end of the tub, applying a vitreous enamel coating interiorly of the complete tub and firing the coated tub.

2. A method of making a vitreous enameled sheet metal article having a slightly curved portion approaching planar shape which is subject to buckling during firing comprising preforming a plurality of blanks each containing a part of said first mentioned portion, which part in each of said blanks is slightly curved, connecting said blanks together with said respective parts in contiguity and with their convex faces facing in the same direction, applying vitreous enamel to the composite blank thus formed and firing the same.

HAROLD W. CLARK. 

